Radiator system



ma '11, I954 K. L. CURTIS RADIATOR SYSTEM 3 Sheets-Sheet 1 Filed 001.. 10, 1945 KENNETH L. CURTIS May 11, 1954 K. L. CURTIS 2,673,394

RADIATOR SYSTEM I Filed Oct. 10, 1945 s sheets-shes; 2

W 0 867 w M 54 444 H KENNETH L. CURTIS y 1, 1954 K. L. CURTIS 2,678,394

RADIATOR SYSTEM Filed Oct. 10, 1945 5 Sheets-Sheet 3 Patented May 11, 1954 UNITED STATES ATENT OFFICE (Granted under Title 35, U. S. Code (1952),

see. 266) This invention is directed to the problem of space scanning with a radiant energy beam, and

relates particulary to means for directing such a beam suitable for use with echo ranging sys terms.

In echo ranging, where it is desired to know the obstacle distribution through a solid angle, the beam is swept 'recurrently over a locus in the desired area, and the range of obstacles at different directions is indicated by the echo receiver. 7

It is a primary object of the invention to provide means for space scanning by controlled variation in the orientation of a directional radiator.

'It is a further object of the invention to provide means for space scanning over a plurality of conical segments.

The present invention contemplates accomplishing these objects by employing a directional radiator mounted on an oscillating shaft, and providing additional means for controlling the direction of the radiator in a plane passing axially through the shaft. Normally, the mounting shaft is vertically positioned and sweeps the beam in azimuth. The second mentioned control tilts the radiator to determine the angular elevation of the beam. In the preferred embodiment, the elevation is shifted between each successive sweep in azimuth to trace the desired sweep pattern.

The invention will be further described in connection with the drawings in which:

Fig. 1 shows a side view of the preferredembodiment of the present invention,

Fig. 2 shows a perspective view of the oscillating mechanism for a directive antenna,

Fig. 3 is a plan view of the antenna mounting shaft and its associated mechanism,

Fig. 4 is a sectional view of the mounting shaft and the cam shaft together with the mechanism carried thereby,

Fig. 5 shows in evolution the exterior surface of a cam member, I

Fig. 6 shows a section along the line 66 of Fig. 5,

Fig. '7 shows in evolution the internal surface of a cam collar,

Fig. 8 shows a sectional view taken along the lines 8--8, of Fig. '7,

Fig. 9 is a view partially in section of the tilt control motor assembly for controlling the angle of tilt of the directional antenna,

Fig. 10 shows in evolution the operative surface of a tilt control cam, and

Fig. 11 shows in evolution the operative surface of a second tilt control cam.

2 The complete scanning unit as shown in Fig. 1 is assembled on frame member l. The directional antenna comprises parabolic reflector 2,

coacting with radiating member 3 to direct a.

beam of radiant energy in accordance with the orientation of reflector. In the usual echo ranging systems, the antenna is employed both for impulse radiation and echo reception. The reflector member is mounted in yoke t for azimuthal orientation, and is tiltable therein on either side at pivots 6 for elevation orientation.

The bearing of the directional antenna is controlled by mounting shaft 5, which is integrally connected to yoke 4. The elevation of the refiector axis is determined by the position of tilt collar l on shaft 5. Collar is coupled to the reflector by link 8 pivoted to lug 9, which is integral with the reflector. Tilt collar 1 is slidably mounted by splining 42 on shaft 5 for axial movement relative thereto under operation of the tilt control cam mechanism.

In the operation of the device, mounting shaft 5 is continuously oscillated to sweep the radiant energy beam around a horizontal path whose elevation is determined by the position of tilt collar 1 during the sweep. By means to be further described, tilt collar 1 is successively positioned for the desired elevation during each sweep oscillation. For this purpose cam shaft is provided, carrying cams I6 and H which are shaped to the desired configurations on their upper surfaces. These cams are selectively operable to contact roller I8 for controlling the tilt collar.

The mean tilt angle is determined by the axial position of the cam members o shaft (5, and for this purpose they are splined thereon, and positionable by tilt control motor 20. The latter raises and lowers the cam assembly on shaft !5 by means of jack screw 2!, as shown in Figs. 4 and 9.

Tilt control motor 20 is coupled to jack shaft 2! through the gear mechanism shown in Fig. 9. This consists of drive gear I H), which engages gear H I journaled at H2 and carrying internally threaded nut H3. The latter externally engages jack shaft 2 I, and it is apparent that the vertical position of the latter may be controlled through suitable operation of motor 20. By this mechanism the mean tilt position of reflector 2 with respect to mounting frame may be selected and through the operation of cam members E6 or I! the reflector will be suitably positioned for each transverse sweep.

Operation of the scanning mechanism is pro vided by drive motor 25, which is coupled to main drive shaft 25 through reduction gear box 21.

Drive shaft 2% simultaneously rotates cam shaft I5, and by a suitable linkage to be described, synchronously oscillates control shaft 5. Shaft 28 carries gear is driving gear 29 on shaft I for operating the cam mechanism.

As best shown in Fig. 2 shaft 26 carries a cardioid cam 3E3 which coacts with followers 32 carried on slide 33. on plat 34 in ways 35, and the assembly is mounted on the upper surface of frame I. Slide 33 at its outer end carries rack section 36, which engages gear 3? on the upper end or mounting shaft 5.

Cam 3c is shaped. to have a uniform dimension crosswise through its center of rotation and consequently operates with continuous contact to each follower 32 to oscillate slide 33 substantially without lost motion. Rack 36 therefore oscillates shaft 5 through gear 3'! and produces the desired horizontal scanning of reflector 2.

Tilt collar l is splined at 42 on shaft 5, so that it is oscillated therewith, as shown in Fig. 4. Annular member 33 is ,icurnaled on the outer surface of collar 7 at 34 and carries member 45, which includes yoke til. Consequently yoke and cam collar I8 do not constrain shaft 5 in its oscillation.

Radiating element 3 is energized through wave guide ml, which passes upwardly through chamber I02. This chamber is formed centrally in yoke 4 which is affixed to the lower end of mounting shaft 5. As shown in Fig. 4 th yoke assembly is journaled on the frame member I at the lower inside edge of chamber I02. Wave guide IIII is coupled to the radiator 3 through guide section I03. The latter is provided with a r0- tatable coupling joint to guide I0! within chamber I02. Such rotatabl couplings are well known in the art, and may be of any desired construction. This coupling is coaxial with shaft 5, and guide section IE3 is rigidly mounted on the yoke to oscillate therewith. A vertically elongated aperture I05 is provided in reflector 2 to permit passage of waveguide section I03 and to provide clearance for the tilting movement of the reflector.

As shown in Figs. 3 and 4, tilt collar I splined on shaft 5 is axially controlled by yoke of member 45. The latter member carries a cam following roller i8 engageable with the tilt con trol cams 56 or I I. As shown in Figs. 1 and 4, yoke 48 is spring pressed downwardly by spring 4| to maintain engagement between the roller and cam surface.

Thrust bearing 4-5 is interposed between yoke 40 and spring 4! to permit the latter to rotate freely with shaft iii. The thrust bearing comprises an outer member 6'! engaging the upper face of yoke 49 and an inner member 48, which is splined on sleeve 563, mounted for rotation with shaft l5. Consequently tilt collar I is continuously maintained in an axial position on shaft 5 controlled solely by cam member IE or IT.

Cam I! is affixed to sleeve 50 intermediate of its length. Sleeve Ell is splined on shaft I5 at 5!, and is journaled at its lower extremity in block 53 by bearing Block 53 is vertically positioned by jack screw 2I which thereby controls the position of cam II. Cam I6 is splined at GII on the outer surface of sleeve 50 below cam I7, and is spring-pressed downwardly thereon by spring iii. The cams I6 and I! are selectively placed in operation by controlling their relative The latter is slidably mounted axial positions. In Fig. 4 cam Iii is elevated and therefore is engaged by roller I8.

The axial position of cam I6 is controlled by floating collar 65, which engages its lower surface. Collar rests on the upper surface bearing 52, and rotates with shaft I5.

As shown in Figs. 5 and 6 the lower neck of cam It is provided with an outwardly extended portion "It. This extension constitutes a cam surface coacting with complementary portions of floating collar 65. The latter are shown in Fig. '7, and comprise a deep recess "I! and a shallow recess I2. A section of floating collar 55 taken through deep recess ii is shown in Fig. 8. In the position shown Fig. 4 cam surface ID of cam member IS rides in shallow recess '32. In order to shift the position of cam It the solenoid actuated member 810 may be extended to engage detent 8| carried on tthe outer face of collar 65. This operation arrests the rotation of collar and causes cam surface "If! to ride up out of shallow recess I2 and around the upper face of collar 65 until it seats in deep recess II under operation of spring SI. The solenoid may then be deenergized to permit retraction of member 813 by a biasing spring. In this position the upper cam surface of It is at all points below the upper surface of cam II, on which roller I8 then rides.

In the embodiment shown the upper face of cam i6 is formed in 4 sectors at successively increasing heights, as shown in evolution in Fig. 10. In Fig. ll. cam I! is shown in evolution and provides only two positions, opposite sectors having the same height. In this case, therefore, the reduction effected by gears 28 and 29 coupling rive shaft 26 to cam shaft I5 is two to one. Each horizontal sweep, of which two occur for each revolution of shaft 25, is transversed While follower Iii dwells on a quadrant of the operative cam surface, and the timing is selected to effect elevational shifts during the extreme positions of the horizontal sweep.

It will be understood that the embodiment shown is exemplary only, and that the scope of the invention will be determined with reference to the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

l. A scanning system comprising a directive antenna, rotatable mounting shaft means carrying the antenna, a drive shaft parallel to the mounting shaft, cam means driven by said drive shaft coupling the drive shaft to the mounting shaft operative under continuous rotation of the drive shaft to oscillate the mounting shaft, a cam shaft driven from said drive shaft at half the angular speed, a first circular tilt cam on the cam shaft having a plurality of first tilt cam surfaces at varying axial positions of said cam shaft, cam follower means engageable with the first tilt cam surfaces operatively coupled with the directive antenna to tilt the same in dependency on the cam means, second circular tilt cam means on the cam shaft having a plurality of second tilt cam surfaces spaced axially of the cam shaft and different in number from the first cam surfaces, and tilt cam positioning means operative to effect engagement of the cam follower and the second tilt cam surface with disengagement of the first tilt cam surface.

2. A scanning system comprising a directive antenna, rotatable mounting shaft means carrying the antenna, a drive shaft parallel to the mounting shaft, cam means driven by said drive shaft coupling the drive shaft to the mounting shaft operative under continuous rotation of the drive shaft to oscillate the mounting shaft, a cam shaft driven from said drive shaft at half the angular speed, a first circular tilt cam on the cam shaft having a plurality of first tilt cam surfaces at varying axial positions of said cam shaft, cam follower means engageable with the first tilt cam surfaces operatively coupled with the directive antenna to tilt the same in dependency on the cam means, second circular tilt cam means, spline mounting means slidably mounting the second tilt cam means around the cam shaft, the second tilt cam means having a plurality of second tilt cam surfaces spaced axially of the cam shaft and different in number from the first 6 cam surface, and axial positioning means connected with the second tilt cam means operative to effect, engagement of the cam follower and the second tilt cam surface with disengagement of the first tilt cam surface.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,050,226 Nixon Jan. 14, 1913 1,559,962 Heinitz Nov. 3, 1925 1,598,433 Fuog Aug. 21, 1926 2,407,305 Langstroth Sept. 10, 1946 2,407,310 Lundy Sept. 10, 1946 2,410,827 Langstroth Nov. 12, 1946 2,410,831 Maybarduk Nov. 12, 1946 2,415,103 Langstroth Feb. 4, 1947 

